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#include "ultra64/asm.h"
#include "ultra64/regdef.h"
.text
/**
* void Mio0_Decompress(void* src, void* dst);
*
* Decompress Mio0 chunk
*/
LEAF(Mio0_Decompress)
lw a3, 0x08(a0) /* compressed offset */
lw t9, 0x0C(a0) /* uncompressed offset */
lw t8, 0x04(a0) /* decompressed length */
add a3, a3, a0 /* compressed start */
add t9, t9, a0 /* uncompressed start */
move a2, zero /* 0 */
addi a0, a0, 0x10 /* move past header */
add t8, t8, a1 /* dst + decompressed length = end */
mainloop:
bnez a2, 1f
lw t0, (a0)
li a2, 32
addi a0, a0, 4
1:
slt t1, t0, zero
beqz t1, read_comp
lb t2, (t9) /* read 1 byte from uncompressed data */
sb t2, (a1) /* store uncompressed byte */
addi t9, t9, 1 /* advance uncompressed start */
addi a1, a1, 1
b next_iter
read_comp:
lhu t2, (a3) /* read 2 bytes from compressed data */
addi a3, a3, 2 /* advance compressed start */
srl t3, t2, 0xC
andi t2, t2, 0xFFF
sub t1, a1, t2
beqz t3, 3f
addi t3, t3, 2
2:
lb t2, -1(t1)
addi t3, t3, -1
addi t1, t1, 1
sb t2, (a1)
addi a1, a1, 1
bnez t3, 2b
next_iter:
sll t0, t0, 1
addi a2, a2, -1
bne a1, t8, mainloop /* continue until decompressed length is reached */
jr ra
3:
lbu t3, (t9)
addi t9, t9, 1
addi t3, t3, 0x12
b 2b
END(Mio0_Decompress)
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